U Joints
 

Need to replace the u joints in my 69 Firebird. 350/th350. Stock rear end.
The rear u joint looks original. The one on the yoke has been replaced at some point and is the culprit, along with the tail seal and bushing.

What I need to know is are the front and rear u - joints the same? Some stores list a front and rear, while other only list one item?

On my 68 350/350 both U joints were/are the same. 1310 series. I'd be surprised if the U joints were different. I doubt that they would be different from the factory. If they are different the yoke on the driveshaft would have had to be changed, along with a different trans yoke. I doubt that would have been done. If you can, do a rough measurement of the u joint width and cap diameter. Different series have markedly different dimensions.

Make sure you replace it with a solid nongreasable one too

I know its a pain but when i install new joints i never trust the grease thats in them i take them apart clean and re'grease with NLG2 marine ... try to find forged made in USA if no USA at least make sure they are forged , not cast

1310 is Chevy "small" U-joint.

Pontiac usually uses the 3R U-joint.

I had swapped rear ends to a 12 bolt from a 69 Camaro. I recall having to replace the pinion yoke (and u joint that blew). 1310 design. I mistakenly thought the front was also a 1310. It is a 3R design.

Pony up the $$ for Spicer U-joints. Everything else is junk.

I like greaseable joints but I also give them a shot of grease with every oil change. If you're lazy, get a non-greaseable u-joint. If you regularly pound on the car hard, get a non-greaseable u-joint as the body is a little more rigid in strength.

You may have to get the driveshaft rebalanced if replacing the yoke. Be on the lookout for vibrations after the work is done.

I didn’t say nongreasable out of laziness. It’s a strength issue.

For hard use you don’t really want a grease fitting creating a weak spot in the stressed corner of the joint.

If you do have a joint with a grease fitting it should be installed such that it’s under compression during operation rather than in tension, so attention should be paid to proper orientation of the joint during installation.

I agree with this.

This isn't to Moog bash, because I've used plenty of their products, but their Ujoints are too long. I read reviews saying that, bought them anyway because they were cheaper and then couldn't get them to go in. Spent a few more dollars on same size spicer joits and they installed easily.

I also agree with solid U joints as a strength concern. My driveline guy told me a solid 1310 was stronger than a greaseable larger joint.

OP has a 350/TH350. You have 100+
cubes on him and a stick. You also
have an aluminum through bolted
9" rear while his is the original 8.2

I understand what you are saying but I still think I would go with the solid U joint. I dont understand the argument against. Very few of us drive the cars in anything that would amount to enough time for a correctly installed Ujoint to go bad. Honestly probably not even long enough for one to require regreasing.

I bought a police interceptor crown vic aluminum driveshaft to use in a project. Those cars dont make a ton of power but they saw a ton of miles. It had solid joints in it. So longevity isn't an issue anyway. Its not as if there is a massive price difference. The solid joints just seem like a superior piece to me for a minimal price difference.

Durability is durability. I was simply saying get good parts. Years ago when I worked at Advance there was a brand called Brute Force. They were solid joints. Never warrantied any of those out. The regular ones that people were of the mind were better because you could grease them came back a lot.

A-body and F-body Pontiacs generally use the S44 (aka 3R) u-joint. Chevrolet generally uses Spicer 1310/1330/1350 style u-joints. The u-joints should be the same front and rear unless the transmission slip yoke was changed to a Chevy 1310 style yoke and/or the differential was changed to a Chevy 10-bolt or 12-bolt which uses a 1310 u-joint. The S44 and 1310/1330/1350 joints are not interchangeable, because other than physical dimensions, the S44 joint is retained by inside clips and the Spicer joints are retained by outside clips. Also, the S44 should be affixed to the pinion yoke by u-bolts and nuts. Spicer 1310 joints generally use straps with hex bolts.

If you still have factory S44 style joints, then I recommend the Dana Spicer 5-795X front and rear. Follow the link to see the different types of u-joints including a combination joint that mates the two series.

https://www.danaaftermarket.com/sear...irebird&sort=1